1. Field of the Invention
This invention relates to a focus detecting device, and more particularly to a focus detecting device using a single photoelectric device.
2. Description of the Prior Art
Various focus detecting devices in which a light image is displaced on the light-receiving surface of a photoelectric device in accordance with a change of the image forming position by an image forming lens and the detection of the focus of the image forming lens is accomplished by detecting the displacement of said image have been proposed in Japanese Open Patent Application Publication No. 15432/1976 and others. The conventional device of this type has used a pair of photoelectric devices and has carried out the detection of the focus from the relative displacement of light images on the light-receiving surface of this pair of photoelectric elements. Such device has encountered the necessity of uniformizing the characteristics of the two photoelectric devices and the necessity of highly accurately arranging the two photoelectric devices in the optical system.